Arnold Coster (born Arnold Schiedam, 1976, Netherlands) is a Dutch mountaineer.
Educated as a mechanical engineer, he became intensely involved with climbing at a young age when he started climbing in the Alps. He moved to Nepal in 2003 to follow his passion of mountaineering.
Coster has summited 5 of the 14 peaks above 8000m. In 2010 he became the first person from the Netherlands to summit Makalu (8481 m).